120 ADDITIONAL NOTES. 



as the same depressing passion operates on the 

 human subject. 



3. In the experiments of Messrs. Allen and 

 Pepys*j it was found that when the air used in 

 respiration was pure oxygen, a very much larger 

 proportion of carbonic acid was generated than 

 in the respiration of atmospheric air. A guinea 

 pig, which furnished 0'88 cubic inch of carbonic 

 acid per minute when breathing atmospheric air, 

 furnished 1*48 cubic inch per minute in one ex- 

 periment, and I'll cubic inch in another, when 

 breathing pure oxygen. A corresponding dif- 

 ference, but to a less extent, was observed as to 

 the results of respiration with atmospheric air 

 and that with oxygen gas in the human subject. 

 It does not appear that these experimentalists 

 observed that the increase in the quantity of car- 

 bonic acid was attended with any increase of 

 temperature ; and in some very curious experi- 

 ments, which were made (by my suggestion) by 

 the late Mr. S. D. Broughton, and which are 

 recorded in the Quarterly Journal of Science, it 

 was found that the temperature of animals, 

 which breathed pure oxygen, not only did not 

 rise above the natural standard, but actually 

 fell considerably below it. 



4. While certain laesions of the nervous system 

 cause a diminution of the vital temperature, the 

 following history justifies the conclusion that 

 there are others which may produce the opposite 



* Phil. Trans. 1808, pp. 415. 417. 420. 



